High-voltage gas blast switch having upstream valves for control of gas movement



F. KESSELRING ETAL' 3,53 HIGH-VOLTAGE GAS BLAST SWITCH HAVING UPSTREAM VALVES FOR CONTROL OF GAS MOVEMENT Filed Feb. 25, 1968 m 7 my United States Patent ware Filed Feb. 23, 1968, Ser. No. 707,562 Claims priority, application Germany, Feb. 28, 1967, S 108,546 Int. Cl. H01h 33/82 US. Cl. 200-148 4 Claims ABSTRACT OF THE DISCLOSURE A high-voltage gas blast switch has a stationary nozzle contact carried in a cylindrical insulation tube. An elongated movable contact entering the tube from one end thereof is movable into and out of engagement with the stationary contact, and carries a valve member which cooperates with a valve seat surrounding the stationary contact on the side thereof facing the movable contact. The chamber below this valve is filled with high-pressure gas which flows through the stationary nozzle contact when the contacts are open. A second valve cooperates with a valve seat on the opposite side of the stationary contact to cut off gas blast after the interruption of an arc, with the second valve protected by a central insulation cone against the effects of hot, ionized products produced during arcing. The insulation cone is surrounded by a movable cylinder which is moved responsive to pressures from the main pressure chamber, which are connected to the cylinder through a valve which is operated by the movement of the movable contact.

This invention relates to high voltage gas blast-type switches, and more particularly relates to a novel valve arrangement for controlling the motion of compressed gas between the cooperating contacts when the contacts are operated.

A primary object of this invention is to provide a novel valve arrangement for high-voltage gas blast circuit interrupters which insures the flow of gas between the contacts regardless of the instant at which the contacts are opened in relation to the A-C current being interrupted.

Another object of this invention is to provide a novel dual-valve arrangement for high-voltage gas blast circuit interrupters in which the valve seats are shielded from the effects of hot, ionized gases created during arc interruption.

Another object of this invention is to provide a novel dual valve arrangement for high-voltage gas blast circuit interrupters in which one valve is upstream of the arc and the other valve downstream of the arc, with both valves being operated in response to movement of the main contact.

These and other objects of this invention will become apparent from the following description when taken in connection with the drawing which shows a longitudinal cross-section of an interrupter structure constructed in accordance with the invention.

Referring to the drawing, a stationary nozzle-shaped contact 1 cooperates with an elongated movable contact 2, which is connected to a lower terminal 3 through a suitable schematically illustrated sliding contact 4. Suitable means (not shown) may be provided for making connection to lower terminal 3. Stationary contact 1 may be circular in configuration and is contained in the cen ter of an insulation cylinder 5, which is closed at its lower end by an insulation cover 6. Contact 1 is rigidly axially positioned with respect to insulation tube 5 by suitable connection means (not shown). Sealing rings 1a and 1b insure a leak-proof connection between the periphery of contact 1 and tube 5. In a similar manner, sealing ring 6a seals the connection between cover 6 and insulation tube 5, while sealing ring 612 insures a leakproof connection between movable contact 2 and cover 6 which, however, permits axial movement of contact 2 with respect to cover 6.

A conductive strap 7 is then electrically and mechanically connected from stationary contact 1 to upper terminal 8, which is also provided with suitable means (not shown) for making electrical connection to the terminal. Again, a sealing ring 8a is provided to insure a leakproof connection between terminal 8 and insulation tube 5. The nozzle-shaped contact 1 has a lower extending pedestal which contains a valve seat seal 9 which is adapted to receive valve plate 10, which is rigidly connected and movable with contact rod 2.

In the position illustrated in the drawing, contacts 1 and 2 are engaged and valve 10 is sealed against valve seat 9 to prevent leakage of high-pressure air or gas contained within the chamber formed between the bottom of contact 1 and the top of cover 6. Sealing ring 9 and plate 10 define a first valve located upstream of the cooperating contacts 1 and 2. A central chamber is formed in the bottom of a downwardly extending pedestal of terminal body 8 which rigidly receives an upwardly extending stem 11a of an insulation cone-shaped body 11. The outer periphery of insulation cone-shaped body 11 contains a sealing ring 12 around its outer periphery, while stem 11a carries a sealing ring 13 about its outer periphery. A hollow cylinder 14, having a large diameter portion 14a and the small diameter portion 14b, is then disposed about enlarged section 11 and stem section 11a, as illustrated, with the enlarged section 14a sealing around seal 12 and small diameter section 1412 sealing around seal 13. Note, however, that these seals are of such a type that would permit the axial motion of cylinder 14, with the bottom of the cylinder moving downwardly and into sealing engagement with seal ring 15, disposed around the upper surface of stationary contact 1. Sealing ring 15, in connection with cylinder 14, forms the downstream valve of the present invention.

A biasing spring 16 is then arranged to bear on top of flange 17 of cylinder 14 to normally bias cylinder 14 downwardly toward engagement with valve 15. The volume 18 within cylinder 14 then communicates through the central channel 19 in valve stem 14 and terminal 8' and then through connection tube 19a which contains a three-way valve 20. Three-way valve 20 consists of an upper plate 21 and a lower plate 22 which respectively cooperate with openings formed in contact 1, as shown, and are carried on an actuating rod 23 which is driven by a crank 24 which is pivoted at pivot 25 on support arm 26 and has its left-hand end pivotally connected to contact rod 2 as at pivot 27. An input conduit 28 is then connected through the bottom of insulation tube 5 and may be connected to a suitable compressor (not shown) which maintains the lower chamber below contact 1 at a relatively high pressure, while the upper chamber is normally connected to the external environment through discharge tube 29.

In operation and assuming the apparatus is in the position shown in the drawing, which is the contact-closed position, with valve plate 21 closed because of the position of crank arm 24, a high pres-sure is maintained in the volume beneath contact 1, and cylinder 14 is held in the position showin since high pressure appears within volume 18 through the opened valve plate 22, conduit 19a and conduit 19. Note that the external pressure on cylinder 14 is a relatively low atmospheric pressure, with the differential pressure across the portion of cylinder 14 connecting sections 14a and 1411 being sufiiciently high to overcome the force of spring 16.

If the interrupter is to be opened, a suitable operating mechanism (not shown) connected to contact 2 moves contact 2 downwardly and an arc will be drawn between contacts 1 and 2. The downward motion of contact 2 causes the immediate opening of valve plate so that high pressure gas will flow from the lower chamber through the central chamber in contact 1 and through the arc drawn between contacts 1 and 2 blowing the are upwardly. Note that the hot arc products will not play upon seal or the lower end of cylinder 14; the lower end of cylinder 14 being screened by the lower conical portion of insulation body 11.

As contact 2 moves down, crank 24 will also rotate in a counterclockwise direction, thereby opening valve plate 21 and ultimately closing valve plate 22. The high gas pressure within volume 18 can now escape through channels 19, 19a and valve 21 into the lower pressure region above contact 1, with the pressure in volume 18 decreasing according to some predetermined rate which may be predetermined by the diameter of the various channels 19 and 19a, the lengths of these channels and, if desired, suitable restricting orifices.

As soon as the pressure within chamber 18 decreases to a value low enough to permit the spring forces of spring 16 to move. cylinder 14, cylinder 14 will move downward and into engagement with sealing ring 15. This then closes the discharge path for air from the lower chamber below contact 1 to cut off the gas blast; sufiicient time being provided to insure that the arc has been interrupted when cylinder 14 engages seal 15. For example, movement of cylinder 14 can be timed by appropriate dimensioning of conduits 19 and 19a so that cylinder 14 engages seal 15 in from 20 to milliseconds after contacts 1 and 2 open.

The switch will now be held in this opened position until the operating mechanism moves contact rod 2 upward and toward the closed position. Valve plates 21 and 22 move upward, back to the position shown in the drawing, so that high pressure is again introduced into volume 18 in order to retract the cylinder 14 to the position shown. Once the contacts 1 and 2 close, valve members 9 and 10 seal so that high pressure below contact 1 is sealed by valve elements 9 and 10. However, for a short interval prior to sealing of valve elements 9 and 10, cylinder 14 will be moved upwardly to permit a short blast of compressed gas through the contacts before they engage in order to provide a short blast of air during contact closing.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A high voltage compressed gas circuit interrupter comprising a hollow cylinder; a stationary contact secured in the interior of said cylinder and sealed to the interior wall thereof; a movable contact movable into and out of engagement with said stationary contact; said stationary contact having an opening therethrough; said movable contact engaging said stationary contact within said opening and on one side of said stationary contact; a first valve seat secured to said first side of said stationary contact and surrounding said opening; a second valve seat secured to the opposite side of said stationary contact and surrounding said opening; a first valve member fixed to said movable contact and movable into and out of sealing relation with said first valve seat responsive to movement of said movable contact respectively into and out of engagement with said stationary contact; and a second valve member movable into and out of sealing relation with said second valve seat; and means connecting said second valve member to said movable contact for sealing and unsealing said second valve member and said second valve seat responsive to movement of said movable contact to respective disengaged and engaged positions with respect to said stationary contact; and means for containing a high pressure gas adjacent said first side of said stationary contact when said first and second valve members are in their said sealed relation; said means connecting said movable contact and said second valve member including time delay means therein; said second valve member comprising a hollow cylindrical body having an open end portion facing said second valve seat and a reduced diameter portion facing away from said second valve seat.

2. The device as set forth in claim 1 wherein said movable contact is an elongated member; said first valve member secured axially to said movable contact.

3. The device as set forth in claim 1 which includes a fixed insulation body supporting said cylindrical body and disposed within the open end portion thereof; said insulation body facing said opening in said stationary contact and deflecting gas flowing from said opening away from the end of said cylindrical body.

4. The device as set forth in claim 1 wherein said connecting means for connecting said movable contact and second valve member includes a gas conduit means extending from said first side of said stationary contact to the interior of said cylindrical second valve member, and valve means in said conduit means connected to said movable contact for opening and closing said conduit responsive to movement of said movable contact.

References Cited UNITED STATES PATENTS 3,043,940 7/ 1962 Leeds ZOO-448.2

3,278,711 lO/l966 Thuries et al. 200-l48.2

FOREIGN PATENTS 1,228,696 11/ 1966 Germany.

1,001,511 8/1965 Great Britain.

ROBERT K. SCHAEFER, Primary Examiner R. A. VANDERHYE, Assistant Examiner 

